Hydrogenation catalyst and process



May zo, 1941.

T. G.v -srRlcKLAND HYDROGENATION ('TALYS'I` AND PROCESS Filed NOV. l2,1958 5%.W ATTORNEYS latented May 20, 19141 HYDBOGENATION CATALYST ANDPRCESS Thomas G. Strickland, Bartlesville, kla., assignor to PhillipsPetroleum Company, acorporation of Delaware Application November 12,1938, Serial No. 240,196

13 Claims.

This invention relates to non-destructive hydrogenation of olefinhydrocarbons. It relates more particularly to an active and ruggedcatalyst suitable for the hydrogenation of various organic compounds,and further it relates to a hydrogenation process for which thiscatalyst is suitable.

v It is an object of this invention to provide a nickel-containingcatalyst suitable for the hydrogenation of organic compounds.

It is a further object of this invention to provide a catalyst that hasa high activity in reactions wherein hydrogen is introduced into anorganic compound. j

Another object of my invention is to provide a catalyst which is highlyemcient'in a process for the non-destructive hydrogenation of normallyliquid unsaturated hydrocarbons whereby saturated hydrocarbons of thesame number of carbon atoms per molecule and same general carbonskeleton are formed.

Still another object of my invention is to provide a process wherebyorganic compounds are purified in the presence of hydrogen and in thepresence of a catalyst.

Yet another 'object of my invention is to provide a process wherebyunsaturated hydrocarbons are purified in the presence of hydrogen and inthe presence of a catalyst in one stage of a process and in anotherstage of the -process are reacted with hydrogen in the presence of acatalyst. A

A further object of this invention is to free large quantities of olefinhydrocarbons of their impurities and subsequently in a separate step tohydrogenate the oleiins so purled.

It is another object of my invention to produce parainic motor fuel fromlow molecular weight polymers of normally gaseous olefin hydrocarbons.

It has long been known that pure olefin hydrocarbons may be readilyhydrogenated to paraffin hydrocarbons in the vapor phase and in thepresence of a catalyst such as finely divided' metallic nickel. It hasalso long been known that unsaturated fatty acids and fats may havetheir high compression engines.

detonate, that is, they operate best on fuels which have high octanenum-bers. The `detonation characteristics of hydrocarbons used as fuelsvary quite Widely with their molecular species; that is, whether theyare paraiiinic, oleflnic, naphthenic, or aromatic; with their molecularstructure, that is, whether the molecules of the hydrocarbons arerelatively simple or highly branched in structure; their molecularweight; and with their concentrations in admixture with otherhydrocarbons. Many fuels are more or less complex mixtures ofhydrocarbons, and this last variable is often of considerableimportance. In addition to these factors relating directly todetonation, other characteristics which must be considered are thestability of the hydrocarbon in the fuel to gum and color formationafter prolonged storage in contact with air and/or water, and thesusceptibility to additions of tetra-ethyl-lead and other antidetonatingagents, that is, the amount of increase in the octane number of a .motorfuel such as the familiar tetra-ethyl-lead.

It has been found that paraiiin hydrocarbons I 'which are normallyliquid, which boil below about 400 F. and which have one or morevbranches in their molecular structure are ideal for fuels for Suchhydrocarbons are extremely stable during long storage, they have highoctane numbers in the pure state and .the effect of these high octanenumbers is not appreciably lost on blending, and it is possible toincrease the octane number of a fuel consisting of such hydrocarbonsconsiderably by adding only small amounts of an agent such astetra-ethyl:- lead.

Olen hydrocarbons corresponding to such desirable paraln hydrocarbonsare now readily Y prepared by the catalyticpolymerization of lowermolecular weight olei'lns. Thus, diisobutylene, corresponding to thewell known isooctane, 2,2,4- trimethylpentane, is readily prepared bypolymerizing isobutylene. Other branched octenes may be prepared by thepolymerization of normal butenes and by the copolymerization ofisobutylene and normal butenes. Similarly, other oleiins, of both higherand lower molecular weights, may be prepared by the polymerization ofolefins and mixtures of olefns having low molecular weights. The olefinhydrocarbon products produced by the simple catalytic polymerizationofsuch low molecular weight olens vary not only with the originaloleilns and mixtures of oleins but 'also with the operating conditionsduring vpolymerization and the catalysts used.

' Thus, commercial products will vary from es- Modern internalcombustion, spark ignition.

sentially pure diisobutylene, mixed with a little triisobutylene, tocomplex hydrocarbon mixtures containing olens having from about six toabout twelve or more carbon atoms per molecule. Most generally it issuch more or less complex mixtures which are produced by commercialpolymerization processes.

In order to produce, from low molecular weight oleiins, motor fuelswhich are paramnic. have high octane numbers and are greatly improved bythe addition of small amounts of tetra-ethyllead, it has been founddesirable to polymerize such oleilns and subsequently to hydrogenate theolefin polymers. When this iscarried out on a laboratory scale: theprocedure 4is relatively simple, the materials being worked with arecomparatively pure, or are easily purified. and simple procedures andcatalysts which are old in the art are quite successful-for thenon-destructive hy droge-.nation of the olefin polymers. However, acatalyst suitable for prolonged and economical hydrogenation in acommercial process is not so readily available. especially whencommercial polymerization products containsmall amounts of impuritieswhich are ordinarily costly to reminum oxide upon an inert support andtreating this material with hydrogen.

Such a catalyst will be hereinafter referred to as nickel-copperaluminacatalyst. I have found that an advantageous method of preparing such acatalyst is to prepare an aqueous solution containing nickel nitrate,copper nitrate, and' aluminum nitrate, mixing with this solution agranulated inert support such as granular pumice stone and evaporatingthe water from this mixture. Such an evaporation may be accomplished byheating this mixture to its boiling point and constantly stirring it asit boils and the water evaporates. As the water evaporates the solutionbecomes more and more concentrated with respect to the salts con--tained therein, and finally the various nitrates vare deposited out uponthe inert support which. is present.

As the evaporation continues, this deposition progresses until all ofthe nitrates are deposited upon the surface ofthe support, andI thecoated or impregnated support nally becomes dried, and the nitrates arethen decomposed in a stream of air, thetemperature gradually beingraised until a final temperature oi about 650 to 750 F., or more hasbeen attained. During this decomposition the nitrates which weredeposited upon the inert support are decomposed andthe intimate mixtureof the oxides of the various metals remain upon the catalyst. 'I'hedecomposition of. these nitrates is accompanied by -the formation ofnitrogen oxides which are very corrosive and obnoxious andthis operationis preferably carried out with the coated particles of the support upontrays which are provided with a dequate means of ventilation so thatthese nitrogenoxides are carried away without injury to surroundingequipment or people.

A modified method of preparing such a catalyst is to soak a body ofsupport such as pumice, composed of particles passing a standard 4 meshsieve and retained by a 10 mesh sieve, in a`concenaia-12,62?

trated aqueous solution of the nitrates for' a half-houror more, atordinary temperatures, such as about 50 to 100 F. After such soaking,the impregnated support is removed from the solution, is dried andheated to` an elevated temperature of 400 F. or more,`whereby the'ni- Atrates are decomposed forming the corresponding oxides.

decomposing the nitrates. This process is repeated until a desiredIamount of the metals in the form of metal oxides is associated on andwith the support. In the case of ordinary pumice, two or three suchtreatments generally suice to make a very active and durable catalyst,containing sufilcient nickel to correspond to between about 1.5 and 5pounds of nickel nitrate (Ni(NOa)2.6H2O) oi nickel nitrate per gallon ofsupport.

After the nitrates have been substantially completely decomposed andonly an intimate mixture of metallic oxides remain deposited on theparticles of the supoprt, the mixtureA is then treated with hydrogen ata mo'regor less elevated tem` peraturesV This treatment is preferablyvcarried out with'the particles of material to be treated placed withinthe hydrogenation chamber in which the catalyst is subsequently to beused. The treatment is accomplished by passing hyi drogen or a mixturecontaining hydrogen over the catalyst. I have at times found itadvantageous to treat the mixture of metal oxides with obtained byheating the mixture of oxides from atmospheric temperatureto an initialreaction temperataure of about 200 F. in astream of -hydrogen and in thereaction chamber, and then- The catalyst so `prepared consists of anintimate mixture which contains metallic nickel and metallic copper andaluminum' oxide, a1- though since it has been prepared by reducing amixture of the metallic oxides, it may also at times contain variousamounts of nickel oxide or of copper oxide or both; In any event I havefound that a catalyst prepared in this manner is highly active inpromoting the non-destructive hydrogenation of olefin hydrocarbons inthe motor fuel boiling range. 'It is also active in promoting the.addition of hydrogen' to all hydrocarbons in this boiling range whichhave unsaturated linkages between two adjacent carbon atoms. such asunsaturated .naphthenes andl aromatics 50 such as benzene. Suchhydrogenation treatment may be carried out with vthe hydrocarbons to betreated; either in the vapor or 'liquid phase or under mixed phaseconditions.- In any case, lit-is preferable that the hydrogenationprocess be carried out atsuper-atmospheric pressure of the order f 200to 2000 pounds per square inch, preferably of the order 'of 750 to 1000'pounds per -'square inch and at temperatures between about 200 F. andabout '700 F., although at thehigher 7o temperatures some decompositionreaction o'f the hydrocarbons may begin to take place. With ,some chargestocks and with veryactive catalysts, only a small superatmosphericpressure may be necessary. Themost desirable conditions of temperatureand pressure for any particular case The resultant material is thenagain .treated by soaking it in an aqueous solution, con-- per gallon ofsupport. preferably `about 3 poundshydrogen onlyv at a low temperature,such as is` l iay be readily detenined by trial by one skilled in theart.

I have found that in many hydrocarbon mixtures containing olens whichare to be nondestructively hydrogenated there are present deleteriousamounts of impurities which are harmful to a hydrogenation catalyst suchas the one just described. If the original mixture from which the olefinpolymers were formed contained some sulfur compounds, these impuritiesmay consist of small amounts of sulfur-containing compounds. However, itis much easier to purify these normally gaseous hydrocarbons from suchsulfur compounds than it is to purify the heavier hydrocarbon material,so that in many cases the oleiin polymers will be prepared fromrelatively pure hydrocarbons and will contain little ifl any deleterioussu-lfur compounds. However, no matter what the source of the olefinpolymers they will have been contacted with air, probably in thepresence of water, and a certain small amount of oxygen-containingcompounds such as organic peroxides will have been formed If theseoxygen-containing compounds are allowed to remain in the hydrocarbonmixture containing olefin polymers to be hydrogenated, I have found thatthey will react preferentially in the presence of thehydrogenatingcatalyst forming water, and such reaction will tend topoison the catalyst and shorten its useful life.

I have now found that these oxygenated compounds may be quite readilyreacted with hydrogen in the presence of a catalyst and in fact theywill react with hydrogen formingwater in the presence of. anickel-containing catalyst which. has become deactivated for thenon-destructive hydrogenation of olefin hydrocarbon. Thus I have foundthat, when a hydrocarbon mixture containing olefins which havebeenpurilied, is passed along with hydrogen over a nickelcontainingcatalyst, such as the nickel-copperalumina catalyst described herein,the catalyst gradually becomes deactivated, that is, it promotes thehydrogenation reaction lessvand less readily, and it is necessarygradually to increase the temperature of operation in order to maintainthe content of unreacted olen in the eiuent from the hydrogenationchamber -at zero or at a small negligible value. As this temperatureofhydrogenation is increased to above about 650 to .675 F. decompositionreactions set in and be present in the reacting mixture in too largeamounts, and that in order to maintain the olefin content of the mixturecharged to the hydrogenation step at a suiilciently low value, it isdesirable -to recirculate a portion of the saturated eilluent from thehydrogenation chamber. This may be accomplished by directly .recycling aportion'of the eilluent from the hydrogenation chamber back to the inletof this hydroge'nation chamber. However, in the purification of a chargestock containing deleteriousoxygen containing compounds, it is notnecessary that this material be mixed with recyclev stock, although attimes such may be desirable? for other reasons. Thus, I have found thatI may pass such an impure charge stock in admixture with a limitedamount of hydrogen over a spent catalyst at a temperature which isappreciably lower than that at which said spent, catalyst was last usedto eil'ect substantially complete hydrogenation of olen hydrocarbons toparailn hydrocarbons, such as a. temperature of about 10G-200 F. lowerthan a previous temperature of hydrogenation, whereby theoxygen-containing impurities are reacted with hydrogen and water isformed. The water is thenremoved from the effluent of this iirstchamber, the dried eliiuent stream is then mixed with a portionof thehydrogenated eiiluent of a second catalyst chamber and this iinalmixture is then passed, in the presence of additional hydrogen, over acomparatively fresh nickel-containing catalyst at a temperature betweenabout 200 and 650 F. whereby the olen hydrocarbons are nondestructivelyhydrogenated and the nickel-containing catalystused has an extensiveperiod of life.

One method whereby olefin hydrocarbons in the motor fuel boiling rangemay be puried from contaminants such as oxygen-containing compounds andmay subsequently be non-destrucshows diagrammatically one arrangement ofapthe hydrogenation step must be discontinued or,-

if continued, a new batch of catalyst must be used. After such use thecatalyst is called a deactivated catalyst. However, I have found that acatalyst which has becomedeactivated for this reaction still retainssufficient activity so that it may be used as a catalyst for purifyingfresh olen charge, in the presence of hydrogen, from oxygen-containingcompounds which may be present. Also, I have found that such treatmentmay be successfully carried out at a temperature'appreciably below thena1 temperature at which the catalyst was previously used. Thus, theimpure charge stock may be passed over such.l a spent catalyst in thepresence of small amounts of hydrogen at-a temperature which is notsumciently elevated to induce decomposition reactions of the hydrocarbonor to promote appreciable hydrogenation and these oxygen-containingcompounds will react with the hydrogen present, whereby water is formedand lvery little if any of the olefin hydrocarbons are hydrogenated. Theeilluent from this purication step/may be then freed of water by coolingstock may consist essentially completely of oley paratus suitable forconducting my process.

Referring now tothe drawing, an olefin-containing hydrocarbon mixture ispassed to the z process through conduit III and is compressed to asuitable pressure by pump II. Such a'charge fin hydrocarbons in thegasoline boiling range which have been produced by polymerization of.

From pump II the olens continue on through conduit I2, sufficientquantities of hydrogen are introduced through conduit I3 and arecompressed to a'desirable pressure by pump I4 and admixed with thehydrocarbons in conduit IZ,

passing froml pump I4 to conduit I2 through.

conduit I5. The mixture of hydrocarbons and hydrogen passes through heatexchangers I 6 and I1 and through valve I8 and is introduced at the topof the catalyst chamber 20. As may be alumina catalyst, and a reactionbetween hydrogen and the oxygen-containing compounds takes place thereinwhereby the oxygen-containing compounds disappear and water is formed.The effluent from catalyst chamber 20 passes through conduit 25, heatexchanger I6, cooling coil 26 and through conduit 21 to drying means 26.Drying means 28 represents any convenient apparatus for removing waterfrom the eilluent of the catalyst chamber 20. The effluent may simply bedried by cooling this material and separating out the water whichcondenses and which would collect in the bottom of aseparator, andremoving the water through conduit 30 controlled by valve 3|. However,it will generally be more desirable to supplement or replace this simplemeans by a dehydrating agent such as calcium chloride and the like.

The mixture containing purified olefin hydrocarbons passes from thedrier 28 through conduit 32 controlled by valve 33 and is compressed orboosted to a suitable pressure by pump 34. The effluent fromthe pump 34passes through heat exchanger 35'l into conduit 36 and is there admixedwith recycled stock which passes through conduit 51, which will behereinafter described. Additional hydrogen can be added as necessary tothe mixture in conduit 36 through conduit 31 and is compressed to asuitable pressure by pump 38. This hydrogen should be added in amountssuch that the total amount of hydrogen present'in the subsequentportions of conduit 361s appreciably more than the amount of hydrogenrequired to react with the olens present and preferably should be atleast about twice the molar equivalent of the olefin hydrocarbonspresent. The mixture of hydrocarbons and hydrogen is passed throughvalve 39 and enters hydrogenation chamber 40. If desired, valves 4I and42 may be openedand valve 39 partially or completely closed and all or apart of the stream may be passed'through the heating coils 43 which arepositioned in a heater such as the furnace 44 whereby the temperature ofthe material entering hydrogenation chamber is ,sufficiently elevated toinitiate reaction under the pressure which exists 'at the inlet of thishydrogenation chamber, and in the presence of the catalyst containedtherein.

Hydrogenation chamber 40 may be any one of a number of different typesof hydrogenation chambers. Thus, it may be a long, vertical cylindricalcatalyst chamber such as is diagrammatically shown, with a singlelargebed of catalyst resting upon a screen or similar support near thebottom of the chamber, or a series of such supports may be placedthroughout the chamber and small individual beds of catalyst may rest onthese supports. Although the hydrogenation reaction isr highlyexothermic, the process arrangement shown which includes an appreciableproportion of recycled hydrogenated material permits the hydrogenationreaction to be carried out in a chamber such as 1s illustrated withoutan undue temperature rise as the material passes the temperature. Suchchambers are well known in the art and may be readily adapted ltomyprocess, as may any other known type of chamber.

When using a fresh, highly active catalyst such as thenickel-copper-alumina catalyst herein described, the initial inlettemperature need not be greater than about 200 to 300 F. Under theseconditions of operation the material passing through the catalystchamber will undergo a temperature rise of about 50 to 150 F. above the.temperature at the inlet of this chamber. The amount of this temperaturerise will depend upon the olefin concentration in the mixture beingpassed through the catalyst chamber and upon the heat losses from thecatalyst chamber` by radiation and the like. By controlling thesefactors properly the amount of temperature rise may be suitablycontrolled as desired. As the process continues I have found that theactivity of the catalyst tends to decrease slowly, even when usingpurified hydrocarbons, and as this takes place it is necessaryto alterone or more of the variables so that the effluent hydrocarbons from thischamber will be substantially completely hydrogenated. As it isgenerally desirable to maintain a substantially constant flow ofhydrogenated material from the process, I prefer to counteract thisdecrease in the activity of the catalyst by gradually increasing thetemperatureand/or the pressure of the inlet material. This raising ofthe temperature and/or pressureis continued as is necessary until thetemperature of the emuent material has reached a value between about 650and '150 F. and preferably the use of any particular batch of catalystis stopped when` the eiiluent temperature has attained a value of about675 F. At this point the 'process can be continued using a freshcatalyst as will be readily understood by those skilled in the art..

The chamber containing deactivated catalyst which has been removed fromthe hydro'genation of olefin hydrocarbons in this manner may beconnected, by means of conduit not now shown, to substitute in thepurification of the raw olefin charge in place of the catalyst chamber20.

The eilluent from the catalyst chamber 40 h passes through conduit 45and valve 46 and may be passed in indirect 1heat exchange relationshipin heat exchanger 35 with fresh olefin hydrocarbons being` charged tothe process, and isv the most preferable manner of operating the processa substantial lproportion of the eflluent of catalyst chamber 40 ispassed through conduit 54 and valve 65 and is suitably boosted inpressure by pump 56 and passed by conduit 51 into the conduit 36 wherebyit is mixed with fresh olefin charge to the hydrogenatlon chamber 40 asrecycled stock adapted to dilute the olefin charge. 'I'he amount ofparamn hydrocar.

bons recycled in this manner is generally at least equal to the amountof olefin hydrocarbons in conduit 36 and most preferably is 2 to 10times that amount. Since a substantial 'excess of hydrogen is preferablyused, this recycle stream fmay also contain some of the excess hydrogen.It may sometimes be found more desirable to pass the entire eiiluent ofthe hydrogenation EXAMPLE 2 As an example of the operation of my processY for the nondestructive hydrogenation of gasoline chamber 40 from theprocess through conduit 4l controlled by Valve 48, remove the hydrogentherefrom and pass only a portion of the hydrocarbon eilluent back tothe process. If this procedure is followed this saturated hydrocarbonmaterial to be recycled may again be introduced to the process alongwith the hydrogen through conduit 31 shown.

EXAMPLE 1 As an example for the preparation of an activenickel-containing catalyst which will be termed a nickel-copper-aluminacatalyst, an aqueous solution was prepared which contained three poundsof nickel nitrate (Ni(NOs)z.6I-I2O), 0.35 pound of copper nitrate(Cu(NOa)z.3iI-I2O) and 4.5 pounds of aluminum nitrate (Al(NAO3)s.9l-I2O)for every gallon of pumice subsequently added. This solution containedonly enough water to maintain the salt in solution at about roomtemperature. Crushed pumice stone, which had been graded so that it wasbetween 6 and 8 mesh to the inch in size, was added to this aqueoussolution and the mixture was heated until the water was boiling, themixture being Ithoroughly stirred. This heating and stirring wascontinued until all of the water had evaporated leaving behind pumicestone on which there was deposited in intimate mixture the variousni-trates just enumerated. This mixture was then heated to a temperaturebetween 660 and 750 F. while passing air over it, whereby-'the nitrateswere decomposed and a residue of intimately associated metallic oxideswas left upon the pumice granules. These oxides were then reduced bypassing hydrogen over the material at about atmospheric pressure and ata temperature of about 680 F. The catalyst so prepared was then used tohydrogenate oleiin hydrocarbons which are normally liquid and boil belowabout 400 F., in admixture with 3 volumes of paraflinic hydrocarbons ofapproximately the same boiling point. The catalyst prepared in thismanner contained 0.616 pound of nickel per gallon of catalyst andhydrogenated approximateely 285 gallons of olens per gallon of thecatalyst before the catalyst was deactivated.

In order to determine the effect of changing the various amounts of thevarious salts used, a series of catalysts was prepared in which thesevalues were altered, the methods of preparation being otherwise similarto those of the catalyst just described. The eiectiveness of these othercatalytic materials in the hydrogenation of olefin hydrocarbons in thegasoline boiling range is shown in the accompanying table. 4

Dependence of catalyst life on nickel, alunnum and copper contents(catalyst, 6`8 mesh) Per cent by weight Ghaslligxitrir Percentage of pergallon cata* olefin in total Ni A1 cu lyst pmduct 87. 3 v 0. 0 12. 7 168. 8 79. 2 20. 8 0. 0 107 1. 6 7l. 1 18. 6 l0. 3 150 1. 5 58.9 15.4 25.7 189 l. 5 39. 6 10. 4 50. 0 192 1. 5

*No completely saturated product was made.

boiling range olefin hydrocarbons, a hydrocarbon mixture consistingessentially of oleflns formed by the polymerization of the olefinhydrocarbons in a hydrocarbon mixture containing propylene andbutylenes, along with the impurities which have been formed in .theseoleiins'by storing it in contact with air and with water, was used as acharge stock.v This mixture con-tained perv cent of olefin hydrocarbonand slightly less than 2 per cent of oxygen-containing compounds. Thischarge stock was. mixed with a limited amount of hydrogen, in thisinstance aboutl 5 cubic feet of hydrogen per gallon of liquid ole'ncharge stock, both.` measured at atmospheric pressure and temperature.This mixture was compressed to about 750 pounds per square inch andheated to a temperature of about 400 F. and passed at about thistemperature over a nickel-copper-alumina catalyst which had bei comedeactivated for the non-destructive hydrogenation of purled olenhydrocarbons. As Athis mixture passed over the catalyst in the catalystchamber a reaction occurred consuming hydrogen and forming water fromthe oxygen-containing compounds. The eiiluent of the chambercontained2.2 cubic feet'of hydrogen per gallon of liquid hydrocarbon,and the olefin content of the liquid hydrocarbon had only been reducedto 80 per cent of the total hydrocarbons. For every gallon of liquidhydrocarbon charged there was produced about one-half ounce of Water.

The emuent from the chamber is cooled somewhat and passed over solidcalciun'i`- chloride which removes the water from the stream. The

hydrocarbon mixture thus purified is mixed with approximately threetimes as much paramn'hydrocarbons of substantially .the same boilingpoint which is obtained from a subsequent step in the process. Hydrogenis then added so that the final mixture contains about one part byvolume of liquid olefin, three parts by volume of liquid paraffinhydrocarbon and about 80 cubic feet of hydrogen measured at standardtemperature and pressure for every gallon of olen hydrocarbon present.This mixture is heated to a temperature of about 450 F. under yapressure of 750 pounds per square inch and passed over a relativelyfresh nickel-copper-alumin'a catalyst in a second catalyst chamber. Asthe material passes-through-the catalyst chamber a reaction occursbetween the hydrogen and the unsaturated hydrocarbons and heat isliberated so that by the time the materials reach the, 'exit of thecatalyst chamber they are at a temperature apl proximately higher than.the inlet tempera-lv ture` The total olen content of .this eilluentstream is about 0.6 per cent by volume of the hydrocarbons present. Aportion of the euent stream consisting of about three-fourths of thetotal volume of the hydrocarbons present is separated and recycled withadditional olens comlng from the purication step. The other portion ofthe hydrocarbons is separated from the hydrogen which accompanied it andconsists of over 99 per cent of paraflln hydrocarbons and the octanenumber of these hydrocarbons is Somewhat above 90.

All the catalysts shown in the table of Example l contained 0.308 poundof nickel per gallon of catalyst. and the weight ratio of nickel toaluminum was held constant at a value of about 3.8:l, except for thecatalyst where no alumina at the start of the run the eiiluenthydrocarbon material from the hydrogenation chamber was completelysaturated, but as the runs progressed '9. small amount of unsaturatedhydrocarbons was present in the effluent, and it was necessary toincrease the temperature to keep this amount negligibly low with aconstant throughput.

Other runs indicated that an increase in the absolute amount of nickelpresent in the nal catalyst increased the total amount of polymer whichcould be hydrogenated by a given volume `of catalyst before it becomesdeactivated. Ihave also found that only limited amounts oi almina needto be present, and that if the amount of alumina is increased so thatthe ratio by weight of nickel to aluminum is less than about 3:1 nosubstantial benet results upon further increases in the alumina content.In general, I have found that, of the three metals present. there shouldb e between 5 and 25 per cent by weight of aluminum, which of course isprobably present as alumina,- and between and 50 per cent by weight ofcopper, which is probably present as metallic copper. The most activecatalysts contain 10-20 percent of aluminum (as alumina), and -30' percent of copper, with the ratio of nickel to aluminum at a value of about3.8:1.

- Although pumice stone has been mentioned as a support, I wish itunderstood that I may. 'use any desirable or available inert support,such as porous porcelain, silica gel, quartz, infusorial earth,asbestos, wood charcoal and the like. Such supports are not fullequivalents of each other, but produce catalysts which are quitesimilar. However, although I may use activated alumina as a support, Ihave not found'that the deposition of a mixture of nickel and copperoxides or hydroxides or the like upon activated alumina will produce acatalyst at all similar to 2,242,627 was present. lExcept for thosecatalysts sonoted,

previous use. The olefin hydrocarbons containing such impurities arereadily treated without being diluted with paraflinic material, and Ihave found that I may successfully operate the process when the amountof hydrogen which accompanies such impure olens is about -40 per cent ofthe total amount yof hydrogen which would be required to saturate allthe oleflnic material present. However, an appreciable proportion of thehydrogen will pass through the purification ste'p unreacted, and verylittle of the olennic material will be reacted with hydrogen to formprailln hydrocarbons. If it is desirable for other reasons, it should bepossible to pass all the hydrogen 'which will be needed in the entireprocess along with the olen through the las or the equivalent of mynickel-copper-alumina catalyst herein described.

Furthermore, although I have found that itis important that the oxidesof nickel, copper and aluminum should be intimately mixed togetherbefore reduction, they need not always be formed by decomposition of thenitrates. Thus, 'alternative but not completely equivalent methods ofpreparation include the coprecipitation of compounds of these metalsupon supports from a solution 'of them which has been treated with analkali, an alkaline carbonate or the like. Copreciptates so'formed maybe dried and heat treated a'nd subsequently treated with hydrogen, asdescribed in connection with the nitrates. The temperature of treatmentwith hydrogen is often preferably quite low. Thus, I have pro- .duced avery active catalyst by placing a batch of the unreduced supported oxidein a hydrogenatlon catalyst chamber at about atmospheric temperature,gradually warming the material up to an initial hydrogenatingtemperature of about 300 F.. while passing a stream of hydrogen over it,and immediately starting a hydrogenation run.

In my hydrogenation process, using a spent catalyst in a catalyticpurifying step, I have found that a catalyst which has become inactivefor the hydrogenation of'olen hydrocarbons at a temperature of aboutG-700 F., will be quite active for promoting the reactionl ofhydrogenwith oxygen-containing impurities at a temperature of about 35o-450 F.,that is, at about 200 F., or more below the final temperature of itspuriiication step of my process. If the hydrogen charged to the processalso' contains impurities such as oxygen or the like, it may bedesirable to pass all thehydrogen through vthis chamber so that it mayalso be purified. As long as low temperatures are used for the reactionof oxygencontaining impurities, little reaction of hydrogen with theunsaturated hydrocarbons will take place.

If, in the hydrogenation step, only that amount of hydrogen is usedwhich is just in excess oi that required to react withi the unsaturatedhydrocarbons present, it will be possible to produce a saturated productonly after a very long reaction time. For this reason I prefer to use atleast twice the amount of hydrogen needed, and preferably about fivetimes as much hydrogen should be passed through thehydrogenation step.In this manner a low reaction time and a high throughput will result.Since unreacted hydrogen can be recycled in one manner or another, nooverall loss need result.

I claim:

1. A catalyst comprising nickel, copper and alumina, and containingbetween 5 and 25 per cent by Weight of the metals as aluminum and.between 10 and 50 per cent by weight as copper.

2. A process for the nondestructive hydrogenation of unsaturatedhydrocarbons, which comprises passing a hydrocarbon material containingunsaturated hydrocarbons-,along with free hydrogen over anickel-copper-alumina catalyst under conditions of temperature andpressure adapted for nondestructive hydrogenation of said unsaturatedhydrocarbons, said catalyst characterized by its relative compositionand its method of preparation which comprises impregnating an inertgranular supporting material with an aqueous solution of the nitrates ofnickel, copper, and aluminum to incorporate therewith compounds 'of saidmetals, the amount of nickel corresponding to between 1.5 and 5 poundsof crystalline nickel nitrate per gallon of supporting material, withbetween 5 and 25 per cent by weight of said metals as aluminum andbetween 10 and 50 per cent by weight as copper, subjecting the treatedsupport to an elevated temperature 'to decompose said compounds formingan intimate association of the oxides of said metals on said granularsupporting material, and treating the resultant granular material withfree hydrogen at a temperature suiiicient to reduce at least a portionof said oxides and below 700F.

3. A process as claimed in claim 2 in which the catalyst has a ratio ofnickel to aluminum of about 3.8:1.

4. In the catalytic, non-destructive hydrogenation of olen hydrocarbonsin the gasoline boilstantially completely dehydrating the eiiiuent ofsaid treatment, adding to said efuent parain hydrocarbons in an amountsuch that the ratio of paraffin to olen hydrocarbons is between 1:1 and10:1, also adding additional hydrogen to said eiiiuent in an amount inexcess of the amount oi that required to react with the olefinhydrocarbons present, and passing theresultant mixture over a relativelyfresh nickel-containing catalyst under reaction conditions oftemperature and pressure for a time such-that substantially all of saidolen hydrocarbons are non-destructively hydrogenated. i

5. In a non-destructive hydrogenation of olen hydrocarbons in the motorfuel boiling range wherein a hydrocarbon mixture containing said olefinsis passed in the presence of hydrogen over a catalyst comprising nickel,copper and alumina and which is subject to poisoning by oxygencontainingimpurities associated with said olens, the improvement which comprisespassing said olefins associated with said impurities over a deactivatednickel-copper-alumina catalyst `in the presence of 20 to 40 per cent ofthe hydrogen which would be required to saturate said olefins and undera superatmospheric pressure and a temperature suiilcient to react saidoxygen-containing impurities with hydrogen forming water, removing waterfrom the eiliuent of said treatment, adding to said eiiiuent at least anequal volume of paraiiin hydrocarbons of similar boiling range, addinghydrogen to .said eiuent in an amount such that the total hydrogen isappreciably in excess of that required to saturate completely theunsaturated hydrocarbons contained therein `passing said resultantmixture at a reaction temperature and pressure over a solidi catalystcomprising nickel, copper and alumina whereby unsaturated hydrocarbonsbecome sat' urated with hydrogen, and recovering hydrocar bons from atleast a portion of the efliuent ofsaid catalyst.

6. A catalyst comprising nickel, copper and alumina, and containingaluminum and nickel in the ratio of about 1:3.8 by weight and copper inan amount between 10 and 50 per cent by weight of the total amount ofynickel, copper and aluminum.`

7. A catalyst suitable for the non-destructive hydrogenation of olefinpolymer in the motor fuel boiling range and comprising an intimateassociation of the hydrogen-reduced oxides of nickel, copper andaluminum upon an inert granular support, containing aluminumA and nickelin a ratio of about 1:3.8 by weight, copper in .an amount between 10 and50 per cent by weight of the metals present, and containing be- 6 tweenabout 0.3 and 1.0 pounds of nickel per gallon of granular supportingmaterial.r

8. An improved process for the nondestructive hydrogenation ofunsaturated hydrocarbons,

of a solid granular catalyst comprising an intimate association ofreduced oxides of nickel, copper, and aluminum on a granular support,the amount of nickel being between about 0.3 and 1.0 pound per gallon ofsupport, with between and 25 per cent by weight of said metals asaluminum and between 10 and 50 per cent by weight 'of said metals ascopper, maintaining the ow of said unsaturated hydrocarbons over saidcatalyst substantially constant over an extended period of time, andduring said period of time progressively raising the temperature oftheprocess a's said catalyst becomes deactivated to a maxi- A mumtemperature of about 650 F. to effect a substantially constant andcomplete nondestructive hydrogenationA of said unsaturated hydrocarbons.r

9. An improved process for the non'destructive hydrogenation Aof olefinhydrocarbons in the motor fuel boiling range, which comprises subjectinga stream containing such olen hydrocarbons together with at least anequal volume of parafiin hydrocarbons of a similar boiling range and anexcess of free hydrogen, under a hydrogenation pressure between 200 and2000 pounds per square inch at a hydrogenation temperature and for aperiod of time adapted to effect substantially complete nondestructivehydrogenation of said olefins, to the action of a body of solid granularcatalyst comprising an intimate association of reduced oxides of nickel,copper and aluminum on a granular support. the amount of nickel beingbetween about 0.3and 1.0 pound per gallon of support, with between 10and 20- per cent by weight of said metals as laluminum and between 15and 30 per cent by weight of said metals as copper, maintaining the flowof said olen hydrocarbons over said body of catalyst substantiallyconstant over an extended period of time, and during said period of timeprogressively increasing the said hydrogenation temperature as saidcatalyst becomes deactivated to a maximum temperature of about 650 F. toeffect a substantially constant and complete nondestructivehydrogenation of said olefin hydromove said nonhydrocarbon impuritiesfrom said i material with reaction of only a minor part of saidunsaturated hydrocarbons, admixing with the eiliuent of said deactivatedcatalyst saturated hydrocarbons in an amount suiiicient to result inf amixture containing saturated and unsaturated hydrocarbons in a ratiobetween about 1:1 and 10:1, subjecting the resultant hydrocarbon mixturein the presence of a substantial excess of free hydrogen to a body ofrelatively fresh catalyst comprising reduced intimately associatedoxides of nickel, .copper and' aluminum on a granular supportingmaterialat a reaction temperature and pressure adapted to eiect substantiallycomplete nondestructive hydrogenation of said unsaturated hydrocarbons,each said catalyst containing between 0.3 .and 1.0 pound of catalyst pergallon of supporting material with between 5 and 25 per cent by weightof said ment which comprises using as sucha catalyst a granular materialcontainlng 0.3 to 1.0 pound of nickel per gallon of support. withbetween and 20 per cent by weight o1' said metals as aluassociated withnonhydrocarbon organic impurities, which comprises hydrogenating saidolens in the presence of a catalyst comprising a reduced intimatelyassociated mixture of oxides of nickel, copper and aluminum on agranular support, the amount o nickel being between 0.3 and 1.0 poundper gallon of support, with between 5 and 25 per cent by weight of saidmetals as alumilnum and between 10 and 50 per cent by weight ascoppeninitiallypassing said oleilns and free hydrogen atan elevatedtemperature and pressure over a body of such'a catalyst which has becomedeactivatedby use as a hydrogenation catalyst to effect a removal ofsaid organic impuritiesxwith reaction of only a minorpart of said olefinhydrocarbons, admixing with the efliluent of said initialtreatmentparamn hydrocarbons of the same boiling range in an amount such that theratio of paraifln to olen hydrocarbons is. betweenV 1:1 and 10:1,passing'the resultant mixture together with excess hydrogen under asuperatmospheric pressure at a rate which is substantially constant overan extended period of time over a second body of such a catalyst whichhas not become deactivated by use and maintained at a nondestructivehydrogenation temperature, progressively during said period of timeraising the temperature as said catalystbecomes deactivated to a maximumtemperature of about 650 F. to eiect a substantially constant andcomplete nondestructive hydrogenation of said oleiins during said periodof time, and recovering paraillns so produced from the eilluent of theprocess.

12. In the nondestructive hydrognation 'of olen hydrocarbons in themotor fuel boiling range wherein a hydrocarbon mixture containing saidolens is passed in the presence of hydrogen over a catalyst comprisingthe reduced oxides of nickel, copper and aluminum on a support and whichis subject to poisoning by oxygen-containing impurities associated withsaid olens, the improveminum and between and 30 per cent by Wieght ascopper, passing said olens associated with said impurities over such acatalyst in a deactivated state in the presence of to 40 per cent of thefree hydrogen which would be required to saturate said oleflns and undera superatmospheric pressure and at a. temperature adapted to f reactsaid oxygen-containing impurities with sultant Imaterial tains thedesired hydrogen to form water, removing water ,from the eluent of saidtreatment, adding to the reparamn hydrocarbons of similar boiling rangein an amount such that the ratio of paramns and oleilns is between 1:1and 10:1, also adding f ree hydrogen in an amount such that the totalfree hydrogen present is substantially in excess of that required tosaturate completely said oleflnsI passing the resultant mixture oversuch a catalyst in an ac'- tive state at a hydrogenation pressurebetween 200 and 2000 pounds per square inch and a temperature greaterthan 200 F. and not greater than about 650.F., and recovering paraln hydrocarbons so ,produced from at least a portion of the efiiuent of saidactive catalyst.

13. A catalyst suitable for the promotion of nondestructivehydrogenatlon o1' normally liquid olefin hydrocarbons in the motor fuelboilingv range, comprising a hydrogen reduced intimate association ofoxides of nickel, copper and aluminum as the sole catalytic ingredientson a solid granular supporting material, containing betweenV 0.3 and 1.0pound of nickel per gallon of said granular supporting material, withbetween 10 and 20 per cent of said metals as aluminum and between 15 and30 per centof said metals or copper, said intimate association of oxideshaving been produced by treating said supporting material with aconcentrated solution of the nitrates ofsaid metal, drying anddecomposing nitrates associated with said supporting material, andrepeating said treatment until said material conamount of said metals.THOMAS G. STRICKLAND.

